The pharynx serves multiple and diverse roles—mastication, breathing, swallowing, speaking, taste and smell, heat, humidify and filter air, protect airway. This single structure serves diverse and highly complex functions, many of which may not be carried out simultaneously. For example, the pharynx is a structure shared by both the respiratory and digestive pathways and acts as a mechanical “switch” to direct incoming air and solids to the appropriate anatomical systems during breathing and swallowing.
During normal respiration, structures of the pharynx assume positions that maximize the patency of the airway. As air is inhaled, tonic activation actively maintains pharyngeal position and phasic activation via the negative pressure reflex resists vacuum-induced changes in pharyngeal position. During normal swallowing, the pharynx propels food and fluid caudally while simultaneously positioning the airway to prevent aspiration of the food and fluid materials into the lungs. Indeed, swallowing is a coordinated pattern of activity involving more than 50 muscles throughout the upper airway and is generally divided into oral, pharyngeal, and esophageal phases.
Because the pharynx is situated at the literal crossroad of the respiratory and gastrointestinal intakes, pharyngeal structural and/or postural dysfunction may result in a variety of disorders including obstructive sleep apnea, dysphagia, snoring, and acid reflux/GERD. In addition to the immediate health concerns introduced by this assemblage of disorders, many of these disorders are associated with an increased risk of additional comorbidities such as heart attack, stroke, hypertension, diabetes, development of carotid artery atherosclerosis, pulmonary aspiration and aspiration pneumonia, among others.
Existing treatments for pharyngeal disorders such as apnea include continuous positive air pressure (CPAP) devices, surgical interventions, weight loss, medication, changes in sleeping position and/or dental appliances; many of these treatments suffer from limited effectiveness or compliance. Implantable monitor devices are under development that monitor thoracic pressure, blood oxygenation, or the bioelectric activity of the diaphragm, intercostal muscles, upper airway muscles, or the efferent nerves associated with these muscles. Other implantable devices have been described that terminate apnea using drug delivery, atrial overdrive pacing or electrical stimulation of the nerves or muscles that control respiratory activities. To date, the potential for the development of effective methods of preventing and/or treating disorders associated with pharyngeal dysfunction remains unfulfilled.
A need in the art exists for additional methods of detecting, preventing, and/or treating adverse pharyngeal conditions and/or treating pharyngeal disorders such as sleep apnea, snoring, dysphagia and/or GERD.